High-frequency apparatus



Feb. 14, 1950 1.. F. soRG 2,497,564

HIGH-FREQUENCY APPARATUS Original Filed May 2, 1945 2 Sheets-Sheet 1 INVENTOR. LLOVD 50/96 "kwam A TTO/PNE Y Feb. 14, 1950 L. F. SORG 2,497,564

HIGH-FREQUENCY APPARATUS Original Filed May 2', 1945 2 Sheets-Sheet 2 4 3 37 I I'Ifi- 5.

IN VEN TOR.

LAM D F 50/?6 ATTORNEY Patented Feb. 14, 1950 HIGH-FREQUENCY APPARATUS Lloyd F. Sorg, Garden City, N. Y., assignor to The Sperry Corporation, a corporation of Delaware Original application May 2, 1945, Serial No. 591,485. Divided and this application October 11, 1946, Serial No. 702,871

5 Claims.

This invention relates to mechanism for tuning electron discharge apparatus and is particularly concerned with tuning mechanism for reliably and accurately controlling electrode spacing in electron discharge apparatus. The present application is a division of my application Serial No. 591,485, filed May 2, 1945, now Patent No. 2,466,058 granted April 5, 1949.

The invention concerns mainly mechanism for obtaining and maintaining parallel association and relative displacement of electrodes in electron discharge apparatus of the type wherein an electrode beam is coupled in energy exchanging relation with one or more oscillating ultra high frequency fields. In its preferred embodiment about to be disclosed, the invention will be described as applied to control of electrode spacing in ultra high frequency electron discharge apparatus of the kind usually characterized as electron velocity modulation apparatus.

As disclosed in United States Letters Patent to Varian No. 2,242,275, the output frequency of electron velocity modulation apparatus may be controlled by variation of the spacing of electrodes between which are disposed portions-of the ultra high frequency field or fields traversed by an electron beam. This is true whether the electrodes comprise grids or other elements interposed in the path of the electron beam, or are apertured to surround the electron beam, or are otherwise arranged between the electron beam and associated field.

United States Letters Patent No. 2,250,511 discloses in Fig.2 an electron discharge device of the type to which the preferred embodiment of the present invention is applied. This device comprises an alternating ultra high frequency field coupled by a pair of spaced electrodes to a uni directional current electron beam which passes from a suitable cathode or other source through the field portion between the electrodes toward a negative reflecting electrode. The latter returns the beam back through the field portion between the pair of spaced electrodes. In each traverse of the pair of spaced electrodes, the electron beam exchanges energy with the field. During the first ity modulation, the electrons travelling between a the electrodes are speeded up or slowed according to the instantaneous direction of the field acting thereon and such tends to create electron grouping in the beam as the faster moving electrons overtake the slower, the instantaneous grouping being a function of the frequency of f other characteristics according tc accepted thecries), the electron beam returns through the portion of the field between the spaced pair of electrodes and is thereby coupled to the field in such relation thereto that the field extracts ultra high frequency energy therefrom by a process which is the reverse of that obtaining during the first passage. This is accomplished because the transit time of the electrons on the reflector electrode side of their coupling with the field is chosen such as to permit optimum grouping of the electrons in the beam and the association of such grouping in proper phase with alternation of the field betwen the electrode during the return passage to deliver more energy to the field than is extracted therefrom. This theory of velocity modulation'which has been widely accepted is explained fully in said Patents No. 2,242,275 and No. 2,250,511 to which reference is made for further detail, but it will be understood that the mechanism of the invention is independent of Such theory of operation.

Experience has indicated that probably the most reliable practical way of varying and controlling frequency in the abovedescribed apparatus is to vary the electrode spacing thereby varying the characteristics of the field between the spaced electrodes and consequentlythe character and degree of coupling between the electron beam and the field. It has further been ascertained that parallel association of the electrodes is preferable as obtaining optimum coupling between the electron beam and field and that maintenance of parallelism between these electrodes as they are displaced to vary the frequency is an optimum mechanical and electrical condition.

For that reason various attempts have previously been made to provide tuning mechanism for obtaining parallel displacement of such electrodes but to my knowledge. noneof these mechanisms are in commercial use probably because of mechanical complexity and non-uniform operation.

My invention provides a reliable and accurate tuning mechanism for'p'a'rallelly relatively displacing electrodes such as above characterized. Since such mechanism may be provided for adaptation to existing electron discharge devices as well as originally built with the device, the invention is such as to embrace the tuning mechanism both separately and in combination with the electron discharge device as will appear in the claims.

With the above in mind, it is a major object of the present invention to provide a novel tuning mechanism for accurately and reliably obtaining parallel association and relative displacement of spaced electrodes adapted to be coupled to an electron beam in electron discharge apparatus. 1

A further object of the invention is to provide an electron discharge device having spaced parallel electrodes in energy exchanging association with an electron beam and including novel tuning mechanism for controlling parallel relative displacement of the electrodes.

A further object of the invention is to provide a novel multiple lever tuning mechanism interposed between spaced electron permeable sections of an ultra high frequency discharge device and adjustable for effecting accurately parallel movement of said electron permeable sections toward or away from each other.

A further object of the invention is to provide a novel ultra high frequency tuning mechanism for regulating the spacing of twoparallel electron permeable electrodes wherein movement of an adjustable control member transverse to the desired direction of relative movement or said electrodes is converted to parallel movement of said electrodes toward or away from each other.

Further object of the invention will presently appear as the description proceeds in connection with the appended claims and the annexed drawings wherein:

Figure 1 is a side elevation of an electron discharge device illustrating especially certain details of a parallel motion tuning mechanism according to the present invention;

Figure 2 is a side elevation similar to Figure l but mainly in section illustrating more details of the tuning mechanism;

Figure 3 is a top plan view, partly in section substantially along line 33 of Figure 2, of the device of Figures 1 and 2, illustrating further details of the electrode spacing adjustment linkage of the tuning mechanism of Figure 1;

Figure 4 is a fragmentary top plan view partly in section on line 4-4 of Figure 2 illustrating especially the mounting plate for the tuning mechanism; and

Figure 5 is a substantially isometric viewof the movable linkage of the tuning mechanism of the device of Figures 1-4.

Referring to Fi ures 1 through 5, inclusive, the illustrated embodiment of the invention includes an electron discharge device I 1 having a pronged base l2 sealed to a lower envelope portion i3 which is preferably a metal stamping having fixed thereto a transverse platform in the form of a relatively heavy rigid annular metal plate M. Arranged in spaced parallelism with plate M is a second relatively heavy rigid annular metal plate I5 which, as illustrated in Figure 2, is afiixed to a cup-shaped metal stamping comprising a substantiall rigid cylindrical shell of a cavity resonator Hi adapted to contain an ultra high frequency field as will appear.

A pair of parallel grids l1 and I8, preferably but not necessarily of the type shown in Figure 3 at 22, are mounted respectively centrally of the upper rigid end wall of resonator shell 55 and on the adjacent end of a tubular stamping I9 disposed ceaxially of envelope portion l3 and aflixed rigidly thereto as by silver soldering. Grids l1 and i8 are disposed in the path of an electron beam emitted from a cathode 2i and passed through an accelerating grid or like electrode 22 fixed upon stamping 13 in coaxial alignment with the beam and grids I! and i8. Grids H, !8 and 22 are parallel. Above grid I1 and coaxial with the resonator is mounted a metallic cup-shaped electrode 23 which is rigidly mounted and insulated electrically from the walls of shell H3 in an envelope portion 24 above the shell. Electrode 23 is conductively connected to a platform M as by screws 3!.

potential may be applied thereto during operation.

Resonator I6 is preferably a relatively shallow hollow cup-shaped metallic shell of cylindrical transverse section having its lower end wall opposite grid ll closed by an annular flexible diaphragm 25 of beryllium copper or suitable highly flexible and fatigue resistant material which has its outer periphery rigid with the cylindrical side wall of shell l6 and its inner periphery rigid with stamping 59. By this construction it will be apparent that the grids i7 and i8 are flexibly and resiliently inter-connected by flexible and resilient wall 26 of resonator It. This connection permits'the spacing of grids I1 and 8 to be selectively varied, and below will be described mechanism for accurately maintaining and varying the relative parallel spacing of grids l1 and 88 for controlling the output frequency of resonator Hi.

As clearly illustrated in Figure 2, grids H and iii are rigid with parallel plates M and I5, respectively, so that parallel relative displacement of these plates toward and away from each other will automatically result in similar parallel relative displacement ofgrids H and 1.8. According to the invention I provide parallel motion producing mechanism interposed between plates l4 and 15, such parallel motion being permitted and controlled in part by the resilient nature of -de formable wall 25 of resonator shell Hi.

In addition to deformable wall 26 and shell 16, plates i4 and 15 are interconnected by a series of equally circumierentially spaced tension springs 29, preferably three in number, and the cooperating parallel motion producing mechanism to be described.

Parallel motion producing mechanism As illustrated best in Figure 4, the parallel motion producing mechanism is chiefly supported on the upper side of lower plate 14 by means of a generally U-shaped mounting plate 3% fixed to Near the outer periphery of plate Id, mounting plate 3% has secured rigidly thereto an upstanding pivot post 32 whichis bifurcated to receive a depending lug 3 3 rigid with a post fixed to the generally horizontal leg '34 of a tuning lever 35. A. pivot pin 36 extends through lug 33 and post 52 to provide a pivot about which lever 35 may rock 'on an axis disposed generall perpendicular to the desired direction of relative movement of grids l7 and i8 and the direction of the electron beam from cathode 21,

As illustrated best in Figure 5, the lower horizontal leg 3 of tuning lever 35 is bifurcated and is provided at both terminals with upwardly and outwardly bent portions providing tabs 3! and 38 disposed at a common higher lever than the'remainder of leg 34. Depending from tabs 31 and 38 are hard, preferably spherical-ended, bearing elements 39 and 41 rigid with leg 34 and adapted to bear on the upper flat surfaces of adjacent ends of an oppositely facing generally U-shaped yoke lever member 42.

Yoke lever 42 is rockably supported at two spaced points by upstanding bearing pivot members 43 and 44 which, as illustrated in Figure 4, may be rigid with or integral parts of mounting plate 39. Bearing members 43 and 66 have hard bearing terminals 45 and 4'6, respectively, which are preferably spherical and adapted to seat with similarly shaped sockets'45' and 46 formed in metallic terminal cap 25 by which a negative II he bottom surface o y The upper surface of yoke 42 is formed with shallow, preferably spherical, bearing recesses 41 and 48 for the seating of the similarly shaped hard lower ends of struts 49 and 50, which are threaded in plate I5 for the purpose of initially adjusting and maintaining the spacing of plates I4 and I5 in cooperation with the action of springs 29. There are three of these struts, the third strut 5| having its lower hard spherical end bearing in a similarly shaped recess 52 formed in the upper surface of leg 34 of tuning lever 35 as indicated in Figure 5.

Struts 49, 50 and 5| may simply be ordinary threaded bolt-like elements rotatably threaded in plate I5 and bearing on the yoke and tuning lever, respectively, but are illustrative of a special compound thermal compensation type which prevents ambient temperatures from altering the frequency of resonator I6. However, the present invention contemplates the use of any equivalent mechanical adjustment between plates I4 and I5 and is not limited to the illustrated thermal compensating type of struts but may embody any suitable struts or devices having equivalent function. Struts 49, 5|] and 5| are preferably equally spaced circumferentially and equidistant between springs 29.

In operation, it will be obvious that tuning lever 35 is supported for transverse pivotal movement about pivot 36 and rocks thereon in a path which is non-parallel with the desired relative displacement motion of grids I1 and I8 produced by such pivotal movement. Springs 29 and struts 49 through 5| act in opposition to each other. Springs 29 are of such heavy value that they follow all strut adjustments and take up any mechanical play occasioned by looseness in the threaded struts. As lever 35 rocks clockwise about pivot 36 in Figures 1 and 2, it will be seen that this will lower that portion of lever 35 which is on the right side of pivot 36 in Figure 2 and which contacts strut 5|, thereby permitting tension springs 29 to pull plates I4 and I5 toward each other at this point. Simultaneously and similarly the portion of the tuning lever comprising tabs 31 and 38 is raised, thereby permitting springs 29 acting through struts 49 and 50 to rock yoke 42 counterclockwise about pivots 45 and 46 and pull plates I4 and I5 toward each other at these points. The combined action of springs 29, yoke 42 and tuning lever 35 is such that when lever 35 is rocked clockwise in Figure 2, the spacing of parallel plates I4 and I5 is varied parallelly and, since grids I1 and I8 are parallel to those plates desired parallel displacement of grids I! and I8 toward other is obtained.

When tuning lever 35 is rocked in a counterclockwise direction in Figure 2 about pivot 36, it raises the portion of leg 34 on the right side of pivot 36 thereby raising strut 5| against the force of springs 29 and tending to separate the plates I4 and I5 at this point. The tabs 31 and 38 are simultaneously caused to bear down on yoke 42 and rock yoke 42 clockwise about its pivots 45 and 46 to cause simultaneous upward displacement of struts 49 and 50 against the opposition of springs 29. Thus when lever 35 is rocked counterclockwise uniform parallel separational displacement of plates I 4 and I5 and consequently grids I1 and I8 is thereby effected. Grids I1 and I8 follow faithfully the relative movements of plates I4 and I5, so the above described adjustment afiects parallel relative displacement of grids I! and I8 in both directions.

It is known that variations in spacing of resonator grids provides variation of the character of the 6 field within the resonator and so changes the frequency characteristics of the resonator that the output frequency extracted on coaxial terminal 53 may be accurately and reliably variably regulated by control of the position of tuning lever 35.

The structure of resonator I6 is preferably similar to that illustrated in United States Letters Patent No. 2,345,642 to which reference is hereby made for further detail as to such structure or explanation of the effect of variation of grid spacing on the resonator frequency.

M icrometer mechanism for adjusting tuning lever As illustrated in Figures 1 and 2, the electron discharge device of the invention is preferably mounted upon an instrument panel P by means of a relatively heavy bracket 54 having an upright leg 55 secured rigidly to the panel as will be described, and a lower horizontal leg 56 secured rigidly to plate I4 as by extension of screws 3|.

Referring now to Figures 2 and 3, a threaded trimming shaft 51 is mounted for rotation within an internally and externally threaded tuning shaft 58 which has secured thereto as by set screws 59 an outer cylindrical drum 6| by which it may be manually rotated. Shaft 58 in turn is rotatably threaded and supportedin an internally threaded bushing 62. Bushing 62 has an enlarged head 63 seated in a suitable recess in bracket leg 55 and extends through an enlarged opening in panel P. Bushing 62 is also externally threaded to receive a lock nut and washer assembly 64 which when tightened secures both bushing 62 and bracket 54 to the panel. Shaft 58 carries a longitudinally extending spring finger 65 adapted to fit with a notch 66 in a bushing extension member 51 which surrounds shaft 58 and is internally threaded upon bushing 62.

Bushing extension 6'! has secured thereto, as by nut 68, the inner drum 69 of the micrometer so that drum 69 is stationary with bushing extension 61. Trimmer shaft 51 has at its outer end an enlarged manual knob II and at its inner end a rounded bearing tip I2 adapted to engage the upright leg of tuning lever 35. A snap ring I3 is mounted in a suitable annular recess at the end of trimmer shaft 5'! and may abut the adjacent end of tuning shaft 58 to limit relative axial movement of the two shafts.

In operation, it will be seen that when outer drum 6| is rotated it positively rotates tuning shaft 58 within bushing 62. When drum 6| is rotated to advance shaft 58 to the left in Figure 2, the engagement of the end of shaft 58 with snap ring 13 insures that trimmer shaft end 12 advances to the left thereby rocking tuning lever 35 counterclockwise and causing parallel separation of grids I! and I8 and securing frequency regulation of the resonator. Each time drum 5| has turned a complete revolution about its axis, the bend end of spring 65 drops into notch 66 and this can be felt by the fingers of the operator during manipulation of drum 6 I. This notch indicates to the operator that he is in the center of a wave band, fine frequency adjustment within that band being obtainable by rotation of trimming shaft 51. Drum 6| is in effect a coarse adjustment of frequency and each complete revolution of drum 6| effects a displacement of outer drum 6| an axial distance of one scale division I4 on inner drum 59 as indicated in Figure 3. When drum 6| is oppositely rotated, shaft end I2 is withdrawn from lever 35 which follows it under the urge of springs 29, and reverse control of the resonator frequency-is accomplished.

Fine adjustment of tuning lever 35 is accomplished by rotating knob H. This is done when spring 65 is disposed in recess 55, denoting the middle of a wave band, and provides sufficient holding force to insure that rotation of trimming shaft El within tuning shaft 58 does not cause rotation of tuning shaft 58. The threads of trimmer shaft are very fine as compared to those of shaft 58, preferably being of the double lead variety, .and rocking movement of tuning lever 35 is controlled by this fine adjustment.

I have thus provided both a coarse and fine adjustment for controlling pivotal movement of tuning lever 35, and this adjustment, coupled with the mechanism by which parallel relative spatial displacement of grids ii and E8 is assured when lever 35 is rocked, provides a reliable and accurate frequency control which is not available in other mechanisms for tuning cavity resonators to my knowledge.

I have found that the above described parallel motion tuning mechanism provides for an optimum tuning range within the limits of the diaphragm 26, and that the tuning adjustment made available thereby is more even and reliable than can be obtained in prior tuning mechanisms heretofore employed in such devices.

In use of the apparatus, original parallelism between plates l4 and I5 is obtained by preadjustment of struts 49, 5t! and 5! and this adjustment is locked and remains undisturbed during normal use of the apparatus. Once this in-- itial parallel relation of plates It and I5 is set, rocking movement of the tuning lever will insure parallel relative displacement of the grids throughout the entire tuning range permitted by flexure of diaphragm 26.

Rotation of knob H of Figures 1-5 provides an adjustment of resonator frequency through out the full range permitted by the flexible diaphragm of the resonator. Ihis is a distinct advantage over prior lever types of tuner mechanisms wherein a lever acted on only one strut to obtain the desired relative displacement between the grids, the remaining two struts acting only as pivots. Because of the resultant tilting action of the electrodes, the range of tuning in such prior devices was undesirably limited. In the present invention, the available parallel motion permits frequency adjustment over the full range permitted by the resonator diaphragm.

The present invention is also more efiicient and advantageous than previously proposed differentially and fine threaded coaxial tuning mechanisms for obtaining parallel motion of the grids since such differential and fine thread devices are subject to excessive wear and thread jamming because of the large forces required for distortion of the diaphragm, and in the present in vention the force multiplication obtained by the lever system incident to the motion reduction provided to obtain the necessary small tuning movements aids life and efficiency of the tuning mechanism.

Since the invention provides full range tuning, the factory adjustment screws, as at 495l in Figure 1, may be sealed as with wax when the factory setting is complete to prevent unnecessary tampering with this adjustment in the field. The present invention insures optimum progressive and reproductive frequency adjustment of the cavity resonator.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. In tuning apparatus for determining the spacing of electrodes in an electron discharge device, the combination comprising a rockable tuning lever adapted to be operatively coupled to control the spacing between said electrodes, and adjustable frequency control means comprising a rotatable trimmer shaft having its inner end operatively connected to said tuning lever, a rotatable tuning shaft within which said trimmer shaft extends in fine-threaded rotatable engagement, a support on which said tuning shaft is mounted in relatively coarse-threaded engagement, axial displacement of said tuning shaft carrying said trimmer shaft along therewith, and means engaging said tuning shaft for locking said tuning shaft against rotation for permitting fine frequency adjustment by rotation of said trimmer shaft alone.

2. In the tuning apparatus defined in claim 1, said locking means comprising a spring finger engaging a suitable stationary formation in said apparatus once each revolution of said tuning shaft.

3. Tuning control mechanism comprising a rotatable tuning shaft having a relatively large frequency adjustment range, a coaxial trimmer shaft having fine thread rotatably supported within said tuning shaft, and releasable means for locking said tuning shaft against rotation upon predetermined relative rotation of said shafts for indicating different portions of the tuning range of said tuning shaft, said trimmer shaft being rotatable for fine frequency adjust-- ment within that portion of the frequency range of the tuning shaft determined by said locking means.

4. Control mechanism comprising a shaft rotatably threaded in a support, a coaxial shaft rotatably threaded within said first shaft, the pitch of the threads on the outer surface of said first shaft being more than twice the pitch of the threads on said coaxial shaft, axial displacement of said first shaft carrying the second shaft along therewith, and means for preventing rotation of said first shaft for permitting fine adjustment by rotation of said second shaft alone.

5. Control mechanism as defined in claim 4, said last means comprising a releasable spring interlock between said shafts operable upon predetermined relative rotation of said shafts.

LLOYD F. SORG.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,655,054 Gargan Jan. 3, 1928 2,288,539 Morrison June 30, 1942 2,414,785 Harrison et al Jan. 21, 1947 FOREIGN PATENTS Number Country Date 5,080 Great Britain of 1900 Certificate of Correction Patent No. 2,497,564 February 14, 1950 LLOYD F. SORG It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: 7

Column 1, line 13, for the word electrode readelectron; line 57, after ultra insert high; column 3, line 19, for object read ob ects; column 5, line 54, after toward insert each;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 30th day of May, A. D. 1950.

THOMAS F. MURPHY, 7

Assistant Omnmissioner of Patents. 

